<p>A: The <i>wspF</i>* biofilm specialist which has a repeat-insert in the <i>wspF</i> gene, initially cannot swarm but regains swarming by losing the repeat-insert when in swarming selection. B: An engineered <i>fleN</i>*Δ<i>wspF</i> strain also regains swarming despite lacking the <i>wspF</i> gene entirely. Survival analysis reveals that this mutant takes significantly longer than the <i>wspF</i>* to start swarming, but does so eventually. C: A spontaneous mutant in <i>wspA</i> regained swarming in the <i>fleN</i>*Δ<i>wspF</i> background. D-F: Diagram explaining how Wsp mutations enable switching between extremes of biofilm and swarming. When WspA senses an attachment signal, it transduces the signal to other Wsp proteins that phosphorylate protein WspR, which then produces c-di-GMP and the cells form biofilm (D). When WspF gains the insertion mutation, it fails to demethylate. WspR therefore is hyper-phosphorylated even in the absence of an attachment signal. (E). A Δ<i>wspF</i> mutant phenocopies <i>wspF*</i>. However, a spontaneous mutation in <i>wspA</i> enables cell to swarm. This mutation impairs biofilm formation even when the cells are placed under biofilm forming condition (F). G: Compilation of mutations identified from the mass swarming selection experiment started with the <i>fleN</i>*Δ<i>wspF</i> strain that revealed 43 new Wsp-disabling mutations.</p
